Strategies for the implementation of sensors and RF barcodes based on transmission lines loaded with symmetric resonators

Transmission lines loaded with electrically small symmetric resonators are useful for the implementation of sensors and spectral signature barcodes based on symmetry properties. This paper tries to point out and discuss several strategies for the implementation of these devices. Both microstrip and coplanar waveguide (CPW) transmission lines are considered. The loading resonators are split ring resonators (SRRs), stepped impedance resonators (SIRs), electric-coupled LC (ELC) resonators and magnetic-coupled LC (MLC) resonators. Advantages and disadvantages for the different configurations are discussed.